In general, in size adjustment of headwear that can be widely used regardless of a head size, a dome-shaped opening la is formed at a rear surface of headwear 1, and in order to adjust a head circumferential direction length of the headwear 1, size adjustment headwear in which a size adjustment device 100 is installed between both sides of a lower part of the opening 1a is widely used.
When the size adjustment device 100 is formed with, particularly, a male size adjustment member 111 in which a plurality of fastening protrusions 111a are formed at a predetermined gap and a female size adjustment member 113 in which a plurality of fastening holes 113a corresponding to the plurality of fastening protrusions 111a are formed, the size adjustment device 100 has an uncomplicated structure, can be easily produced, and a size thereof can be easily adjusted, and after the size adjustment device 100 is adjusted to correspond to a head size, the size adjustment device 100 is not easily unfastened, and the size adjustment device 100 has a merit that a person having long hair can bind back their hair and extract the hair to the outside through the opening 1a, the size adjustment device 100 is widely used.
However, as shown in FIG. 1, in such type of size adjustment device 100, because the fastening protrusion 111a and the fastening hole 113a are disposed at, for example, a gap of 1 cm, after two fastening protrusions 111a and fastening holes 113a are fastened, when one fastening protrusion 111a and fastening hole 113a are fastened, a size can be adjusted by only 1 cm, which is a fixed size and thus wearers having various head sizes cannot be satisfied.
That is, when a person having a head circumference of 58.5 cm wears the headwear 1 having such type of size adjustment device 100, if a size of the headwear 1 is adjusted to 58 cm, the person may feel that the headwear 1 is small, and when the person unfastens the size adjustment device 100, moves the fastening hole 113a backward by one size, adjusts to a size of 59 cm, and couples the fastening hole 113a and the fastening protrusion 111a, the person may feel that the headwear 1 is large.
Therefore, persons who highly consider wearing comfort of headwear that is well fitted to persons' heads may dislike the headwear having the size adjustment device 100.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.